Leucoencephalopathy with brain stem and spinal cord involvement and raised lactate (LBSL) is a white matter disease that has recently been described based on typical magnetic resonance imaging (MRI) findings.^1,2 These include widespread, homogeneous or inhomogeneous white matter abnormalities, corpus callosum involvement, and selective involvement of certain brain stem and spinal cord tracts. Increased white matter lactate levels are usually found on magnetic resonance spectroscopy (MRS). Clinically, the condition is characterised by a childhood onset slowly progressive course. Here we report two patients who presented with adult onset LBSL and normal lactate on MRS.

Case report

A 23 year old woman and her 25 year old brother were referred to our department because of a slowly progressive gait disorder. At the age of 20 (in the female patient) and 23 years (in the male patient), the siblings had first noted an unsteady gait, stiffness in both legs, and bilateral clumsiness. They had both had normal development, and their former medical history was unremarkable. They had achieved unsupported walking at ages of 14 months (female patient) and 15 months (male patient). Both had been examined during early adolescence, with normal neurological findings. They were the only affected members in their family, and their parents were non-consanguineous.

Neurological examination on admission revealed mild spastic tetraparesis (affecting the legs more than the arms), generalised …